WSP12152

• File Number: 8273.800.10
• Description: Colorado River Basin Salinity Control - Federal Agencies - Joint Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1989
• Title: 1989 Joint Evaluation of Salinity Control Programs in the Colorado River Basin
• Water Supply Pro - Doc Type: Report/Study

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1989 Evaluation of
Salinity Control Programs in the
Colorado River Basin

Introduction

This summary report is a combined
Department of the Interior and Department
of Agriculture effort to fully coordinate and
integrate the respective salinity control
programs authorized in Public Law 98.569,
amendments to the Colorado River Basin
Salinity Control Act of 1974 (Public Law
93.320), Programs needed to achieve the
objectives of Public Law 93-320 and Public
Law 98-569 are shown in figure L The
report describes ml'\ior program activities
through fiscal year 1989.

The Quality of Water Colorado River Basin,
Progress Report No. 14 contains a more
complete summary of agency and unit
activities. Progress Report No. 14, prepared
by the Upper Colorado Region of the Bureau
of Reclamation has been distributed and
covers many water quality parameters.
Limited copies may be obtained by writing
the Regional Director, Upper Colorado
Region, Bureau ofRec1amation, P.O. Box
11568, Salt Lake City, Utah 84147.

Background

The 1989 evaluation was prepared by
updating the 1988 evaluation report
because no changes have been made in the
recommended plan. The 1988 evaluation
used January 1988 prices and adjusted data
to more accurately compare the program
information of the Department of the

Interior (DOl) and the Department of
Agriculture (USDA), and interest or
discount rates (8-5/8 percent) are at the
same base. (See 1988 Joint Evaluation
Report appendix.) Repayment analysis for
the Lower Colorado River Basin
Development Fund are based on the 1988
rate of 9-3/8 percent interest for the years
1988 and beyond.

The CRSS (Colorado River Simulation
System) computer model analysis is
unchanged from the 1988 analysis and no
changes have been made in the depletion
projections developed jointly by Reclamation
and the Colorado River Basin Salinity
Control Forum (Forum).

The salinity at Imperial Dam, without
further controls, is projected to reach an
average total dissolved solids (TOS) of
970 mg/L by the year 2010. Figure 2
provides a historical perspective in addition
to the numeric standard and the projections
at Imperial Dam, It is readily apparent that
without the recommended controls, the
salinity at Imperial Dam is expected to
increase significantly due to projected
normal or below normal hydrologic con-
di tions. Using the salinity projections at
Imperial Dam, salt load reductions required
to maintain an average TDS level at or
below the numeric criteria of 879 mglL are
estimated to be slightly in excess of
1 million tons per year by the year 2010 and
are referred to as the program objective,
Figure 3 shows how the implementation
plan meets the numeric criteria,